With younger women getting breast cancer, national panel lowers mammogram screening age to 40

The previous recommendations from the panel, the United States Preventive Services Task Force, suggested that women make an individual choice on getting mammography from ages 40 to 49.

The new guidelines, first published last year as a draft open for public comment, are propelled in part by concern over rising rates of breast cancer among younger women.

"More women in their 40s are developing breast cancer," said John Wong, one of the task force members and a professor of medicine at Tufts University. "That's been 2% per year increase from 2015 to 2019. Which means screening provides more benefit because the risk of developing breast cancer is higher."

The changes, published Tuesday in JAMA, also bring the task force closer in line with guidelines from other health organizations. The American Cancer Society, American College of Obstetricians and Gynecologists, the National Comprehensive Cancer Network, and others have published guidelines suggesting average-risk women consider starting screening at age 40 or 45. But the task force's recommendations tend to carry more weight, partially because the Affordable Care Act requires health insurers to fully cover task force recommendations with a grade B or higher.

To breast cancer experts, the bottom line is that organizations that issue screening guidelines are coming to a consensus that starting breast cancer earlier than 50 is reasonable and hopefully will lead to "less confusion among women about breast cancer screening," said Janie Lee, a breast imaging radiologist at the University of Washington and the Fred Hutchinson Cancer Center. "The scientific evidence is clear mammography saves lives."

Cancer screening recommendations, in general, balance the benefits of catching cancer early against potential harms. Such harms include unnecessary biopsies in false positive cases and overdiagnoses — diagnoses of tumors that grow so slowly they wouldn't have harmed or killed the patient before they died of something else. Screening more, as in expanding the age range eligible for screening, often helps to save lives but at the cost of additional harms.

In this case, the task force, a rotating group of volunteer experts, felt that dropping the screening age to begin at 40 rather than 50 was well worth the trade-off. Overall, starting screening at age 40 should translate into a roughly doubling of life years gained by catching cancer earlier, since these individuals are younger to begin with, Wong said. It should also save an additional 1.3 lives out of every 1,000 individuals, according to the statistical models that the task force used to inform the recommendations, Wong said.

For Black women in particular, who are more likely to get breast cancer at younger ages and be diagnosed with more aggressive tumors, that rises to 1.8 lives saved out of every 1,000. That provides some hope that lowering the age of screening will help narrow health disparities for racial groups that have long disproportionately suffered from breast cancer mortality and morbidity.

"This is an important step in reducing mortality and helping Black women live longer, but it's not enough to address the health disparity Black women face," Wong said. "We recognize it's not necessarily the screening, it may be what happens after the screening. We are asking health professionals to make sure follow-up studies are done appropriately and timely after a positive mammogram and if breast cancer is detected."

But one cost of lowering the screening age is 500 additional false positive findings out of 1,000 from mammography, Wong said. "In the context of the 1.3 women who are saved, we felt comfortable with that balance of benefits and harms."

For the most part, breast cancer researchers and clinicians seem to agree that starting screening earlier than 50 is a worthy idea. "I think it's a good thing that the task force has embraced the values of screening women under the age of 50," said Robert Smith, the vice president of early cancer detection science at the American Cancer Society.

The exact details there are where experts disagree. For instance, the ACS suggests that women begin screening at age 45 and make a shared decision with their trusted health provider before then. Smith also said that screening could benefit people over the age of 75, depending on their health status, though the task force felt there was insufficient evidence to recommend that. The task force also wasn't convinced that the benefits were worth it to recommend screening annually, although that is what the American College of Radiology suggests.

These recommendations are typically for the "average risk" person. Specifically, that's people assigned female at birth starting at the the age of 40 who don't have very high-risk mutations like BRCA 1 or 2, who don't have a past history of cancer, or who have had a past biopsy or lesion that showed high risk. But even among the group intended for screening recommendations, everyone's individual risk for cancer can still be variable.

Whether you have a family history of cancer, dense breasts, certain genetic mutations, smoke or drink alcohol, or even have a certain occupation, all of these factors can affect your personal risk for cancer. Scientists hope that these factors will one day help inform personalized recommendations for when and how often each individual ought to be screening. Studies are underway to try to better understand that — though they aren't at the point yet where they can be incorporated into broad population guidelines.

"We are definitely moving away from 'one size fits all' recommendations," said the University of Washington's Lee. "Breast cancer screening recommendations tailored both to an individual's characteristics and also their own preferences about balancing benefits and harms is important. The hard part is the time it takes to design, conduct, and report results for clinical trials that provide new evidence required to update guidelines."

There are calculators readily available from organizations like the National Cancer Institute that already provide some estimation for people's individual breast cancer risk, added Douglas Marks, a medical oncologist at the NYU Perlmutter Cancer Center. Patients are free to use such calculators, Marks said, and he thinks it's good to have discussion with their physicians about the results.

"These guidelines should be taken to enhance our global understanding of how some normal risk women should be monitored. But individual patients should be individually assessed," he said.